I forgot to change the subject. My sincere apologies. On Fri, May 23, 2008 at 3:26 PM, Ragi Y. Burhum <[EMAIL PROTECTED]> wrote:
> I guess this is a good time for me to give my two cents. > > A few disclaimers and background : Until last year, I worked at ESRI. I > contributed with some of bug fixes for the PostgreSQL/PostGIS support in the > ArcObjects side of things. I have also been using PostgreSQL and PostGIS for > *many* years now. I follow many blogs (including yours Paul) but don't > usually respond for obvious reasons. I have been known to circulate some > various postings of criticism among places I have worked (or am working) at > like ESRI, MS, etc. Chances are, you are running some of my code in some > O.S. application and you don't even know it thanks to the beauty of Internet > anonymity :) > > That being said, here are a few answers to some of your questions: > > >> >> Date: Sat, 24 May 2008 02:05:14 +0800 >> From: Tim Bowden <[EMAIL PROTECTED]> >> Subject: Re: [postgis-users] PostgreSQL/PostGIS and ArcGIS Server 9.3 >> To: PostGIS Users Discussion <[email protected]> >> Message-ID: <[EMAIL PROTECTED]> >> Content-Type: text/plain >> >> On Fri, 2008-05-23 at 10:15 -0700, Paul Ramsey wrote: >> >> SDE allows you to use ArcMap as a client. That's the main value >> proposition. >> >> > > > That's not entirely accurate. ArcSDE allows you to use the ArcGIS > ArcObjects GeoDatabase Layer. This includes the ArcGIS Server, ArcMap, > ArcCatalog, ArcEngine Apps, and everything that is supported by that layer: > Raster, TIN, Topology, Versioning, Geometric Networks, Network Datasets, > Representations Layers, Annotations, Dimension Feature Classes, Cadastral > Fabrics to name a few. > > > >> Secondarily, there's some stuff, most particularly versioning, that > >> they implement by managing extra metadata in side tables. This is > >> where your concern regarding 3rd party edits to PostGIS data come to > >> reality. If you start mucking with the data, particularly versioned > >> data, outside the SDE environment, you can put it into an inconsistent > >> state. > Mostly everything is implemented by managing extra metadata tables. > However, that doesn't mean that there is not a mechanism for you to work > with those tables directly. As far as versioning goes, multiversion views > allow you to modify the simple features in versioned tables through the SQL > prompt directly and allowing the data to remain consistent. > > > > Ok, versioning is potentially quite valuable, depending on how well it's > > implemented. I imagine the editing problem exists for both inserts and > > updates. Pity, as it would be nice to at least put new geometries > > directly into PostGIS without upsetting SDE. > > You can do this with Simple Features. ArcSDE allows you to 'configure' how > you want to store your geometry in the underlying database. Do you want to > use the ESRI PostgreSQL type? Do you want to use the PostGIS type? etc. Your > choice will have different advantages/disadvantages. > > >> Also, you need some knowledge of the SDE scheme in order to properly > >> *read* the information out of a versioned system with a 3rd party > >> tool, since the data in the tables will include shapes from multiple > >> versions. > >> > >So if I've understood correctly, if you aren't interested in versions, > >but only the latest and greatest geometries, you should be fine doing a > >direct read of the PostGIS geometries. > See above for multiversioned views in regard to versioning. As long as you > are not using ESRI Complex Feature Types (Topology, Geometric Networks, etc) > you are correct. > > >> In general, if you restrict yourself ot reading with 3rd party tools > >> and writing with ESRI tools, or non-ESRI tools working through the SDE > >> API, you should be safe. > >> > > True. > > >> Yes, using SDE effectively castrates the spatial database. It still > >> walks and talks, but it's a shell of the man it was before. > >> > > This is where we disagree. Although hammers are good, sometimes you need a > screwdriver. The right tool for the right job. > > >Ah, but a much cheaper shell than previously available to SDE users > >(with at least 87%(?) of the performance as I vaguely recall from some > >semi-relevant benchmark study)! > Oh... so relative. > Anyway guys, thanks for the great work in PostGIS. Some of us use it and > even evangelize extensively on certain situations... despite getting stabbed > with hate comments every once in awhile. > > Can't we all just get along? :-) > > - Ragi Yaser Burhum >
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